U.S. President Barack Obama's lead over challenger Mitt Romney has narrowed to just two percentage points since the Republican's strong performance in their first debate, according to a Reuters/Ipsos poll released on Friday.

In more bad news for Obama, one in five voters said the Democrat's performance in the contest in Denver on Wednesday made them feel more negative about him and almost a third said they felt more positive about his Republican challenger.

"Romney did well, he was perceived as doing well, and we're seeing the effect of that today," said Ipsos managing director Cliff Young. "Definitely in the short-term now, he's picking up people because of his performance in the debate."

Obama had led Romney by 6 percentage points in the poll released on Wednesday and the edge narrowed to five points - a 48-43 percent lead for Obama - in polling up to Thursday. That was the first including a day of interviews after the meeting in Denver.

It remained to be seen whether his weak performance in Denver will become a long-term problem for Obama. He has two more chances to redeem himself in debates - a second is set for Oct. 16 and the third is on Oct. 22.

The narrowing could just reflect the effect of a flood of coverage after Romney's impressive debate performance, Young said. "The big question is whether this is just a debate effect, or whether the race will get back to status quo," Young said.

More than 9 out of 10 registered voters - 91 percent - said they had seen, heard or read something about the debate, and 54 percent said they thought Romney had done a better job.

Thirty percent said it made them feel more positive toward Romney, a former governor of Massachusetts. That was more than double the 14 percent who felt better about Obama after watching the two candidates go head-to-head.

Twenty percent said the contest had made them feel more negative about Obama, while 14 percent said it made them feel more negative about Romney.

Obama's campaign got a positive jolt on Friday from a surprisingly strong U.S. unemployment report, in which the monthly jobless rate sank below 8 percent - to 7.8 percent - for the first time since January 2009, the month he took office.

That could help him win over the dwindling pool of voters who say they might still change their minds - just 15 percent of those surveyed.

The precision of Reuters/Ipsos polls is measured using a credibility interval. In this case, the poll has a credibility interval of plus or minus 2.7 percentage points for registered voters and 3.0 for likely voters.

The questions specifically about the debate - included in the survey since Wednesday night - have a credibility interval of plus or minus 3.6 percentage points. The base size for those questions was 976 registered voters.

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